Mark Zuckerberg came in at No. 52 with $13.5 billion. Co-founder Dustin Moskovitz, the world's youngest billionaire (he's got eight days on Zuck), premiered at No. 420 with $3.7 billion. Sean Parker made the list for the first time with $1.6 billion. Co-founder Eduardo Saverin was also new to the list at No. 782 with $1.6 billion. Investor Peter Thiel dropped a few places to No. 833 with $1.5 billion. And Russian investor Yuri Milner of Digitial Sky Technologies, another noob, came in near the bottom at No. 1140 with $1 billion. Milner also has the distinction of making Forbes's cover for connecting Silicon Valley and Wall Street and betting early on Groupon and Zynga.

Although each of the newbies is involved in other projects (Parker is involved with Spotify, a hot British music site plans on crossing over to the U.S.), the reason they're on the list has everything to do with Facebook — in particular, the $1.5 billion influx of cash in January that valued the still-private company at $50 billion, more than double what it was last spring. The secondary market is already valuing Facebook at something closer to $65 billion, which shows you just how theoretical those paper billions still are. But between the frenzy in the secondary market and the hype around lists like these, once Facebook goes public next year, some of the Facebook 6 might still make the cut.